IOLs are artificial lenses used to replace natural crystalline lenses of patients' when their natural lenses are diseased or otherwise impaired. Under some circumstances a natural lens may remain in a patient's eye together with an implanted IOL. IOLs may be placed in either the posterior chamber or the anterior chamber of an eye.
IOLs come in a variety of configurations and materials. Various instruments and methods for implanting such IOLs in an eye are known. Typically, an incision is made in a patient's cornea and an IOL is inserted into the eye through the incision. In one technique, a surgeon uses surgical forceps to grasp the IOL and insert it through the incision into the eye. While this technique is still practiced today, more and more surgeons are using IOL injectors, which offer advantages such as affording a surgeon more control when inserting an IOL into an eye and permitting insertion of an IOL through a smaller incision. Relatively small incision sizes (e.g., less than about 3 mm) are preferred over relatively large incisions (e.g., about 3.2 to 5+ mm) since smaller incisions have been attributed with reduced post-surgical healing time and reduced complications such as induced astigmatism.
In order for an IOL to fit through a small incision, it is typically folded and/or compressed prior to the injector entering the eye and depositing the lens, where the lens will assume its original unfolded/uncompressed shape. FIG. 1 is a perspective view of a fully-assembled, conventional, two-piece injector device 10 showing an IOL 30 being expressed from the tip of the device. The basic components of injector device 10 include a proximal body portion 12, a plunger 20, and a distal body portion 14.
FIG. 2 is a perspective view of two-piece injector device 10 with the two-pieces (i.e., a proximal body portion 12 and a distal body portion 14) being detached from one another. Typically, when using a two piece device, an IOL is loaded into one of the distal body portion and the proximal body portion. Subsequently, the proximal body portion and the distal body portion are assembled to ready the device 10 for delivery of the IOL.
When proximal body portion 12 and distal body portion 14 are attached together, plunger 20 can be moved through proximal body portion lumen 12a so that plunger tip 22 engages and pushes the IOL 30 through passageway 14a and out tip 14b (as shown in FIG. 1).
To deposit an IOL through a small incision, an injector as shown in FIG. 1 is provided with a commensurately small tip 14b through which the IOL enters the eye. Tips 14b having small features have been found to be susceptible to damage during shipping and during operating room activities.
Various structures have been suggested to protect the tip. However, such structures can be cumbersome for a doctor or operating room attendant to manipulate in preparation for depositing an IOL.